This application is based on application No. H11-369281 filed in Japan on Dec. 27, 1999, the entire contents of which are hereby incorporated by reference.
1. Field of the Invention
The present invention relates to an image display apparatus, and particularly to an image display apparatus, such as a head-mounted display (hereinafter, referred to as an HMD), that is suitably mounted on the head of an observer while in use.
2. Description of the Prior Art
FIG. 12 shows the optical construction of a conventional, typical HMD. This HMD is provided with a pair of left and right image display devices (1L, 1R), and a pair of left and right eyepiece optical systems (2L, 2R), so as to correspond to an observer""s left and right eyes (EL, ER). In this optical construction, the two-dimensional image displayed on the image display device (1L) for the left eye (EL) is displayed in the left eye (EL) as a virtual image through the eyepiece optical system (2L) for the left eye (EL), and the two-dimensional image displayed on the image display device (1R) for the right eye (ER) is displayed in the right eye (ER) as a virtual image through the eyepiece optical system (2R) for the right eye (ER).
In the HMD shown in FIG. 12, two image display devices (1L, 1R) are used. It is possible to use only one image display device and share the single image displayed thereon between the left and right eyes of an observer. This makes it possible to reduce the costs of the apparatus by the cost of one image display device. However, sharing the image displayed on a single image display device between the left and right eyes requires an optical construction that separates the image between the left and right eyes, which leads to degradation in the quality of the displayed image.
An object of the present invention is to provide an image display apparatus that can be manufactured at lower cost without sacrificing the quality of the displayed image.
To achieve the above object, according to the present invention, an image display apparatus is provided with: a signal input portion for receiving an image signal; an image compensator for electrically compensating the image signal for distortion so that a left and a right image displayed in an observer""s left and right eyes have identical distortion and then outputting a left and right image signal that correspond to the left and right images; a signal switcher for switching between the left and right image signals output from the image compensator so as to output the left and right images alternately chronologically; a single two-dimensional image display device for displaying a two-dimensional image in accordance with the image signal output from the signal switcher; a pair of left and right eyepiece optical systems for directing image light exiting from the two-dimensional image display device to the observer""s left and right eyes so that the two-dimensional image is displayed as a virtual image in the observer""s eyes; and an optical path switcher for time-divisionally switching optical paths from the two-dimensional image display device to the observer""s eyes in synchronism with switching between the left and right image signals output from the signal switcher so that the image light enters either the observer""s left or right eye at a time.